bitcoin core improvement – How are you going to switch a seed that crashed a fuzz check through textual content?

When a fuzz-test crashes it would print the error stack. The highest gives you an thought what triggered the difficulty, and the underside will offer you a text-formatted model of the crashing fuzz seed.

fuzz: ../../src/pockets/check/fuzz/coinselection.cpp:120: void pockets::coinselection_fuzz_target(FuzzBufferType): Assertion `result_bnb->GetChange(coin_params.m_cost_of_change, CAmount{0}) == 0' failed.
==2010034== ERROR: libFuzzer: lethal sign
    #0 0x55c5cfab4841 in __sanitizer_print_stack_trace (/dwelling/murch/Workspace/pr-27585/fuzz-build/src/check/fuzz/fuzz+0x1611841) (BuildId: 7e7dce8b351f3ad01c4e9815f15265d8d7a64c61)
    …
    [skipped]
    …
artifact_prefix='./'; Check unit written to ./crash-05d2df3cebde688a5114737869a65484cecd9f45
Base64: MP3//////wT/LzMBEABL////////Wv///yWyEABLAADoQP//PP//CAAAPQAAAAAAAAAAPQEAAAAAAAAA/V12+w==

To determine what triggered the crash, you should utilize run the fuzzer in opposition to simply the crashing seed, and use your common debugging strategy e.g.:

$ FUZZ=coinselection src/check/fuzz/fuzz crash-05d2df3cebde688a5114737869a65484cecd9f45

In case you are not the writer of the PR that triggered the crashing fuzz check, you may present the fuzz seed to the opposite developer through the base64 encoding on the backside of the error message. Depart them for instance directions like this in a touch upon the PR:

$ echo "MP3//////wT/LzMBEABL////////Wv///yWyEABLAADoQP//PP//CAAAPQAAAAAAAAAAPQEAAAAA AAAA/V12+w==" | base64 -d > crash.enter
$ FUZZ=coinselection src/check/fuzz/fuzz crash.enter

The string within the citation marks is solely the base64 encoding from above.